Electro-mechanical actuators are used in a wide variety of industrial applications such as, for example, machine presses and the like. A typical electro-mechanical actuator includes an electric motor that functions as a source of rotational power to provide torque to a linear actuator mounted adjacent thereto. The linear actuator is configured to convert the torque into a linear force.
Linear actuators typically include a lead screw that is supported for rotation within a housing. The lead screw is connected for rotation with an output shaft of the electric motor, such as by a belt and pulley system. A driven nut is supported on the lead screw and has an inner diameter that corresponds with an outer diameter of the lead screw. As the lead screw is rotated relative to the driven nut, the driven nut travels linearly along a length of the lead screw, thereby converting rotational power into a linear force. A ram is secured to the driven nut for movement therewith. An end portion of the ram extends from the housing and is adapted to transfer the linear force to a desired work piece.
In certain applications involving high press loads, increased ram speeds, or high precision, the linear actuator can experience internal torque forces that are higher than desired internal torque forces. If unattended, the high internal torque forces can result in damage to the linear actuator.
It would be advantageous if linear actuators could be protected from high internal torque forces.